1. Field of the Invention
The present invention relates to a method for manufacturing a liquid discharge head discharging liquid. More specifically, the present invention relates to a method for manufacturing an ink jet recording head discharging micro droplets of recording liquid used in an ink jet recording method.
2. Description of the Related Art
A known example of a liquid discharge head is an ink jet recording head which is used in an ink jet recording method that discharges ink to a recording medium to perform recording thereon.
With the recent demand towards higher image quality and clearer image of printers, it has become necessary to achieve a further reduction in the size of an ink droplet and a discharge port. Thus, it has become extremely important to manufacture and control micro structures such as a nozzle shape with high precision.
Furthermore, with the recent demand towards a further higher image quality of printers, the landing accuracy of ink droplets has become important.
In the related art, a method for manufacturing the ink jet recording head is described, for example, in the specification of U.S. Pat. No. 6,390,606. According to the conventional method, energy generation elements generating an energy used for discharging liquid are formed on a substrate, an adhesion layer is formed on the substrate so as to improve the adhesion between the substrate and a flow path forming material which will be formed later, and an ink flow path pattern made of a dissolvable resin is formed on the adhesion layer. Subsequently, a layer of the flow path forming material used as an ink flow path wall is formed on the ink flow path pattern, a discharge port is formed on each of the energy generation elements by photolithography, and the dissolvable resin is dissolved, and the flow path forming material used as the ink flow path wall is cured.
However, when ink discharge was performed using an ink jet recording head manufactured based on the method described in U.S. Pat. No. 6,390,606, undesirable results were observed such as ink droplets landing on different positions than the desired ones, depending on the diameters of discharge ports, the materials for a discharge port forming member, and the kind of ink.
The present inventors have observed the surface of the discharge ports and found micro particulate matter adhering near the discharge ports. The present inventors have supposed that such particulate matter caused misty ink droplets, called ink mist, generated during the ink discharge to adhere thereto and be accumulated, so that the direction in which the ink droplets are discharged is twisted due to the accumulated ink adhering to the discharge port surface.
As the results of investigation by the present inventors, the following causes are attributable to the adhering of such particulate matter. That is to say, the flow path forming member, the adhesion layer provided between the flow path forming member and the substrate, or an adhesive is dissolved during any of the manufacturing steps and caused to flow to the vicinity of the discharge ports in a later step. In order to physically remove such particulate matter, additional steps for removing the particulate matter and additional machine for removing the particulate matter are required.
Furthermore, as can be seen in recent ink jet recording heads, micro ink droplets of several pL discharged from small discharge ports are easily affected by the ink droplets adhering to the discharge port surface. For this reason, it is desirable to prevent any matter from adhering to the discharge port surface and prevent the adhering matter from affecting discharged ink droplets as much as possible.